The present invention relates to equipment for fiber-optic communications networks, and more particularly, to optical amplifiers and equipment for upgrading optical amplifiers.
Fiber-optic networks are used to support voice and data communications. In optical networks that use wavelength division multiplexing, multiple wavelengths of light are used to support multiple communications channels on a single fiber.
Optical amplifiers are used in fiber-optic networks to amplify optical signals. Typical optical amplifiers are based on erbium-doped fiber coils that are pumped with diodes lasers. Amplifiers may be designed to operate in the C-band (1527-1563 nm) or the L-band (1565-1605 nm). Raman amplifier arrangements may be used to amplify light in transmission fiber spans.
It is an object of the present invention to provide systems based on optical amplifiers and modules for upgrading the optical amplifiers.
This and other objects of the invention are accomplished in accordance with the present invention by providing optical amplifiers with upgrade modules. The amplifiers may be used to amplify optical signals on optical communications links in fiber-optic communications systems. The upgrade modules may be used to add features to the optical amplifiers. For example, the upgrade modules may be used to add Raman amplification capabilities to the optical amplifiers or may be used to expand the optical bandwidth that is handled by the optical amplifiers.